Apparatus for controlling the temperature of a heat exchange medium

ABSTRACT

An apparatus for controlling the temperature of a heat exchange medium in a reverse cycle heat pump system includes within a closed heat exchange medium recirculating path thermostatically controlled heater mount elements and heat rejection panels. The heat rejection panels are cooled by both air flow and evaporative water system which incorporates a header having elongated members which discharge coolant onto the heat exchange panels through a continuous slot whereby a water curtain is formed to completely wet the heat rejection panel surfaces. A storage reservoir can be utilized to conserve the energy of the heat exchange medium.

United States Patent Root [451 Apr. 25, 1972 [54] APPARATUS FORCONTROLLING THE TEMPERATURE OF A HEAT EXCHANGE MEDIUM [72] Inventor:Donald S. Root, 3830 South Cincinnati,

Tulsa, Okla. 74105 [22] Filed: Oct. 19, 1970 [2]] Appl.No.: 82,019

Primary ExaminerCharles Sukalo Attorney-Head & Johnson 57 ABSTRACT Anapparatus for controlling the temperature of a heat exchange medium in areverse cycle heat pump system includes within a closed heat exchangemedium recirculating path thermostatically controlled heater mountelements and heat rejection panels. The heat rejection panels are cooledby both air flow and evaporative water system which incorporates aheader having elongated members which discharge coolant onto the heatexchange panels through a continuous slot whereby a water curtain isformed to completely wet the heat rejection panel surfaces. A storagereservoir can be utilized to conserve the energy of the heat exchangemedium.

6 Claims, 5 Drawing Figures Pmar-mm s m 3,658,123

INVENTOR.

DONALD S. ROOT 7M am PATENTEMPR 25 I972 SHEET 2 OF 3 uvvnvroze. DONALDS. ROOT FIG. 2

ATTORNEYS- APPARATUS FOR CONTROLLING THE TEMPERATURE OF A HEAT EXCHANGEMEDIUM BACKGROUND OF THE INVENTION This invention relates to a heatingand cooling system; more particularly, it pertains to an apparatus forcontrolling the temperature of the heat exchange medium in a reversecycle heat pump temperature control system.

Reverse cycle heat pumping systems have been widely used in large officebuildings and in other installations where the heating and coolingrequirements are of a sufiicient magnitude to justify the expense ofsuch a system. Although the reverse cycle heat pump system provides theultimate temperature control of the individual zones when a liquidexchange medium is used as a source of heat transfer, the cost andcomplexity of the support system; that is the boilers, cooling towers,pumps, pumping controls and field assembly operations, excludes the useof such a system in small installations. It is therefore an object ofthis invention to present an apparatus for controlling the temperatureof the heat exchange medium in a reverse cycle heat pump system whereinall heating and cooling equipment and associate controls are housed in aunitary preassembled enclosure package.

It is a further object of this invention to present an apparatus forcontrolling the temperature of a heat exchange medium in a reverse cycleheat pump temperature control system incorporating therein a storagereservoir which conserves the energy of the heat exchange medium.

It is still a further object of this invention to present an apparatusfor controlling the temperature of a heat exchange medium in a reversecycle heat pump temperature control system which incorporates therein acontinuously flowing curtain of water wetting the entire surface of theheat exchange panels to obtain optimum heat transfer upon command.

SUMMARY OF THE INVENTION Generally the control tower of this inventionhas vertically disposed therein heat rejection panels through whichpasses a stream heat exchange medium recirculated between and throughthe heat rejection panels and reverse cycle heat pumps. Thermostaticallycontrolled heater elements disposed within the circulating path of theheat exchange medium heat the heat exchange medium upon command. Theheat exchange panels are cooled by a curtain of coolant dischargedthereover through a continuous slot in an evaporative system which iscirculated over the heat panels by a thermostatically controlledcirculating pump. The apparatus further includes a multiple speed fanfor creating an air flow through the heat exchange panels for thecooling thereof.

DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall view of aheating and cooling system employing the control apparatus of thisinvention.

FIG. 2 is an exploded view of the heat exchange control tower of thisinvention.

FIG. 3 is an underside view of a distribution grid, an element of theinvention.

FIG. 4 shows an alternate heat rejection panel, an element of theapparatus of this invention.

FIG. 5 is a partial view of the upper portion of a typical heatrejection panel showing the evaporative cooling portion of theapparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1of the drawings, independently operable reverse cycle heat pumping units12A, 12B, 12C and 12D are installed in separate heat zones throughout abuilding or residence. The operation of a reverse cycle heat pump iswell known in the art, and reference is hereby made to U.S. Pat. No.2,715,514 issued to W. S. Stair, dated Aug. 16, 1955, for theconstruction operation of a reverse cycle heat pump.

Generally, a reverse cycle heat pump is a combination heating andcooling device which utilizes a recirculating liquid heat exchangemedium 10 within a certain temperature range as both a heat and coolantsource. Typically the heat exchange medium is water and the temperaturerange is 40 F to F.

Liquid heat exchange medium 10 is conducted through each of the reversecycle pumping units 12, through a feed conduit 14 from a control tower16 where heat exchange medium 10 is either heated or cooled as requiredby the overall demand of the reverse cycle heat pumps. Control tower 16is located adjacent the wall of the building above ground and issurrounded by outside ambient temperature.

After passing through a heating pumping unit, heat exchange medium 10 isdischarged into a common return conduit 18. An ordinary single braidwater hose of proper size can be used for the feed and return conduits14 and 18, since the temperature requirements of the system require noparticular insulation or protection as long as the environment is withinthe aforesaid temperature range of the system.

In some applications, a storage reservoir 20 may be utilized and isburied below ground in areas where the residual ground temperature iscompatible with the temperature range of 40 F to 100 F. The reservoirlocation is not limited to below ground installation but may be locatedin any environment wherein the ambient temperature is within thetemperature range of the system. Also additional heat sources, ifavailable, can be carried through the reservoir to maintain thetemperature range.

Heat exchange medium 10 is pumped from the storage reservoir to theintake of the control tower 16 through a conduit 22. If the pressurehead of the system requires such, a submersible pump 24 can be locatedwithin the reservoir. An inspection hole 26 can be located on the top ofthe-storage reservoir if desired.

Turning now to FIG. 2 of the drawings, there is shown an expanded viewof the internal components of control tower 16. The purpose of thecontrol tower is to stabilize the liquid heat exchange medium 10 at anoperating point within the minimum 40 F and maximum 100 F of the system.Experiments have shown that a stabilizing temperature of 60 Faccomplishes the desired heating and/or cooling requirements of thesystem.

Control tower 16 is housed by a four-sided enclosure 28, of suitablematerial, such as metal, plastic or fiberglass. The enclosure has aliquid-type sump pit 30, in the bottom thereof and an open top 32.Suitable insulation, such as Styrofoam, lines the inner walls ofenclosure 28.

The inner port of a continuously circulating pump 34 is coupled toconduit 22 and operates continuously to circulate heat exchange medium10 in the direction of the areas through a closed path between andthrough the control tower, the reverse cycle heat pumping units and thestorage reservoir. Pump 34 is sized for the flow requirements and numberof reverse cycle heat pumping units to be serviced. Fluidly coupled tothe outlet port of pump 34 and secured to the outer wall of theenclosure 28 is an elongated full flow immersion chamber 36, thephysical size of which is sufficient to encompass heater elements 38 andof a sufficient cross-sectional area to pennit full transfer of heatfrom the heater element to liquid exchange medium 10. Dual electric typeheating elements 38 are shown by way of example only, and are insertedat the upper and lower end of chamber 36. Each of the heater elements isindependently controlled and and actuated at different temperatures bycontrollers 40 and 42 sensitive to the flow path of the exchange medium10. Thus the heater elements are energized in stages and both elementswill be energized simultaneously only when the average temperature ofthe heat exchange medium continues to drop below the preset operatingtemperature of the system. A high temperature cutoff contact is providedto de-energize the heater elements in the event that continuouscirculating pump 34 should fail. A housing 33 secured to one of thewalls of enclosure 28 provides protection from the elements for pump 34and immersion chamber 36.

The outlet of heat chamber 36 feeds the inlet manifold 44 of amultiplicity of heat rejection panels 46 vertically disposed within theinterior of the disclosure. Each of these panels provides multipledownwardly progressing fluid paths which converge into an outlet header48 which in turn is coupled to and feeds conduit 14. Outlet header 48 ispartially submerged in sump pit 30 and provides sufficient heat toprevent freezing of the sump coolant as will be discussed subsequently.Each of the panels is made of heat conductive material and has stampedtherein or otherwise fabricated an upper subinlet header 50 and a lowersuboutlet header 52 interconnected by a plurality of longitudinal heatpaths 54. An inlet port 56 fluidly couples each panel to manifold 44 andan outlet port 58 couples each to outlet header 48. Inlet port 56 andoutlet port 58 are positioned on each panel at diametrically oppositecorners in order to equalize pressure, thereby assuring uniform heatexchange in each of the fluid paths 54. The necessary number of panelsand of heat paths therein are determined by the capacity requirements ofeach particular installation.

Alternately, heat rejection panels 46 may be replaced by the tubulararrangement shown in FIG. 4. In this arrangement a plurality of paralleljuxtaposed metallic tubes 60 such as copper tubes are fed by inletmanifold 44 and discharged into outlet header 48.

At the apex of inlet manifold 44 there is installed a pressure reliefdevice 62 which, if desired, may comprise a pressurized cap covering anopen port for introducing additional exchange medium into the system.

Differentially operated dual heat absorption systems are employed tocool upon demand exchange medium during flow thereof through the heatrejection panels.

Forced air cooling is supplied by an electrical motor operated fan 64mounted within an enclosure 28 upwardly of heat rejection panels 46. Fan64 is thermostatically controlled by a first contact of a multiple stagetemperature sequence controller 66 having the temperature bulb thereofsuitably inserted in the heat exchange medium flow path. A mesh shroud68 secured to top 32 of enclosure 28 permits air flow upwardlytherethrough while providing protection from the fan blades. Ahorizontal air louver 70 received within enclosure 28 intermediate fan64 and heat rejection panels 46 and air intake louvers 72 installed ontwo sides of the enclosure near the bottom thereof are opened bynegative air pressure created by the rotation of the fan blades toprovide an upwardly flowing stream of air around and over the heatrejection panels.

The second cooling system is of the evaporative water type. The bottomof the enclosure 28 as before mentioned includes a sump pit 30 in whichis receiveda liquid sump coolant 74 such as water or a mixture of waterand anti-freeze. A sump pump 76 has an inlet submerged in sump coolant74 and an outlet port 78 which discharges sump coolant concurrentlyupwardly through dual supply conduits 80 to diametrically opposed endsof a distribution grid 82. The actuation of sump pump 76 is controlledby a second contact of temperature sequence controller 66.

Distribution grid 82 is composed of elongated plastic or PVC pipes 84one each mounted directly over each of the heat rejection panels. As isshown in FIG. 3, each of the PVC pipes 84 has in the bottom thereof acontinuous narrow longitudinal slot 86. Due to the surface tensionthereof, a continuous curtain or stream of sump coolant is dischargedthrough longitudinal slots 86 onto a splash pan 88. The width ofcontinuous slot 86 is to be gauged in compliance with the designrequirements of each installation. Splash pan 88 overlays the upperlongitudinal edge of each of the panels which has outer serrated edgesover which the sump coolant flows downwardly onto the panel. Referringnow to FIG. 5 of the drawings, a fiberglass blanket 90 suitably attachedto the PVC pipes by clamps 92 and jacketing both sides of splash pan 88contains the sump coolant therebetween to assure that all of the liquidis directed onto the heat rejection panel. The coolant curtaincompletely wets the metallic surfaces of the heat rejection panel. andgives more effective heat exchange than that provided by a spray-typeevaporated coolant. Additionally considerable less coolant is used thanin spray-type systems and there is no tendency for the water to followthe air.

Referring now back to FIG. 2, a float valve 94 is provided formaintaining a constant coolant level within the sump pit. Additionallythere is also located in the sump pit an electrical solenoid dump valve96. This dump valve is a combination overflow and discharge valveoperated by an electrical solenoid valve electrically coupled to andactuated by a kind program sequence controller 98 suitably mounted inhousing 33. This controller provides multiple time controllerprogramming for other control uses and has one stage or contact presetto open and hold the dump valve for two or three minutes at preselectedtime periods; such periods being at intervals of up to two weeks. Thisholding action allows the float and filler valve to flush outcontaminant from the sump pit and then returnto standby position untilthe next program timing intervals. This sump dump overcomes a permanentcause of deterioration in evaporative systems by periodically riddingthe sump pit of corrosive contaminants.

OPERATION OF DEVICE Upon a call for heat in one of the zones such asthat served by heat pump 12A, the heat pump will absorb a portion of theheat from the liquid exchange medium passing therethrough. Medium 10then returns through conductor 16 to storage reservoir 20 at a lowertemperature. The heat exchange medium 10 in the reservoir then rests foran extended period due to the large quantity of thermal energy in thereservoir with the liquid exchange medium giving up or absorbing heatwith the surrounding environment which is as before mentioned selectedto be within the operating range of thesystem. In some applications andin intermediate operating conditions, this heating and/or coolingtransference may be sufiicient to stabilize the temperature of thesystem.

Upon a demand for heating exceeding the total design capacity of thereservoir, the exchange medium temperature therein will drop and theliquid passing through continuous pump 34 into immersion chamber 36 willactivate temperature controller 40 which in turn energizes one of theheater elements 38. If the temperature continues to fall, the secondtemperature controller 42 will energize the second heater element. Theheating elements continue to operate until the entire reservoir hasreached a minimum acceptable temperature. At this time the system willautomatically be deactivated by temperature controllers 40 and 42.

The heat exchange medium continues to constantly circulate and upondemand from one of the heating zones, the heater elements will again beenergized.

When the overall demand from the heating zones requires cooling, heatexchange medium 10 is returned to the reservoir at a higher temperaturethan that discharged from the control tower. After a preselected maximumtemperature of the reservoir is reached, fan 64 is energized by a firstcontact on temperature controller 66 causing the passage of air upwardlyover the heat rejection panels. If the temperature continues to rise foran extended period of time, the second contact on temperature controller66 energizes sump pump 76 which as before mentioned causes the dischargeof a coolant of water or other suitable liquid over heat panels 46. Bothcooling systems concurrently operate until the temperature of the heatexchange medium in the entire system again falls within the preselectedtemperature range. At such a time, the fan and sump pump are deactivatedand the system remains at rest except for a constantly circulating heatexchange medium. Obviously, if desired, the temperature sequencecontroller could be electrically wired to energize the wetted surfacecooling system first and the dry air system second or other steps ofcooling should be achieved.

As can be appreciated from the description, this invention is designedto contain in one unitized preassembled package all the functionsperformed by the typical dry-type cooling tower,

evaporative cooling tower, liquid immersion heaters, circulating pumps,forced air passage, sump pumps, and heat rejection panels.

During the detailed description of the preferred embodiment specificlanguage has been used for the sake of clarity. However, it is to beunderstood that the language used is for the sake of clarity and not byway of limitation. Such language includes all equivalents which operatein a similar manner to accomplish a similar purpose.

What is claimed:

1. in a heating and cooling system for buildings where a heat exchangemedium is circulated through a plurality of independently operatedreverse cycle heat pumping units, each unit having an inlet and anoutlet for said heat exchange medium, an apparatus for operativelycontrolling the temperature of said heat exchange medium within apreselected temperature range comprising:

an outer enclosure having a bottom, a top and side, said bottom beingleakproof to form a coolant sump;

at least one heat rejection panel disposed within said disclosures, eachof said heat panels having an inlet for receiving said heat exchangemedium from the outlet of said reverse cycle heat pump units and anoutlet in fluid communication with the inlet of said reverse cycle heatpumping units whereby said heat exchange medium circulates in a closedpath between and through said pumping units and said heat rejectionpanels; continuous operating pump for circulating said heat exchangemedium in said closed system; thermostatically controlled heatingelements disposed in said closed heat exchange path and adapted tooperatively heat said heat exchange medium; an evaporative coolingsystem comprising:

an elongated member disposed within said enclosure directly above andparallel with the upper end of each of said heat exchange panels;

said elongated member having therein a continuous longitudinal slot inthe underside thereof;

a pump disposed in said coolant sump in the bottom of said enclosure;

conduit means for fluidly connecting the outlet of said coolant pumpwith each of said elongated members whereby coolant within said sump ispumped into each elongated member and discharged therefrom through saidslot in a continuous curtain onto said heat exchange panel.

2. An apparatus as in claim 1 wherein said elongated member of saidcoolant system is jacketed by a fiberglass blan' ket which contains saidwater therebetween.

3. An apparatus as in claim 1 including a splash pan disposed withinsaid enclosure between and parallel with said elongated member andoverlaying upper end of each of said rejection panels.

4. An apparatus as in claim 1 including a heat exchange medium storagereservoir disposed within said heat exchange medium circulating path;said heat exchange reservoir adapted to conserve the thermal energy ofsaid heat exchange medium.

5. An apparatus as in claim 1 including fan means disposed upwardly ofsaid evaporated coolant system and adapted to create a flow of airupwardly around said each of said heat rejection panels.

6. An apparatus as in claim 1 including an electrically solenoidoperated dump valve disposed within said coolant reservoir and adoptedto automatically flush said reservoir at preselected intervals.

1. In a heating and cooling system for buildings where a heat exchangemedium is circulated through a plurality of independently operatedreverse cycle heat pumping units, each unit having an inlet and anoutlet for said heat exchange medium, an apparatus for operativelycontrolling the temperature of said heat exchange medium within apreselected temperature range comprising: an outer enclosure having abottom, a top and side, said bottom being leakproof to form a coolantsump; at least one heat rejection panel disposed within saiddisclosures, each of said heat panels having an inlet for receiving saidheat exchange medium from the outlet of said reverse cycle heat pumpunits and an outlet in fluid communication with the inlet of saidreverse cycle heat pumping units whereby said heat exchange mediumcirculates in a closed path between and through said pumping units andsaid heat rejection panels; a continuous operating pump for circulatingsaid heat exchange medium in said closed system; thermostaticallycontrolled heating elements disposed in said closed heat exchange pathand adapted to operatively heat said heat exchange medium; anevaporative cooling system comprising: an elongated member disposedwithin said enclosure directly above and parallel with the upper end ofeach of said heat exchange panels; said elongated member having thereina continuous longitudinal slot in the underside thereof; a pump disposedin said coolant sump in the bottom of said enclosure; conduit means forfluidly connecting the outlet of said coolant pump with each of saidelongated members whereby coolant within said sump is pumped into eachelongated member and discharged therefrom through said slot in acontinuous curtain onto said heat exchange panel.
 2. An apparatus as inclaim 1 wherein said elongated member of said coolant system is jacketedby a fiberglass blanket which contains said water therebetween.
 3. Anapparatus as in claim 1 including a splash pan disposed within saidenclosure between and parallel with said elongated member and overlayingupper end of each of said rejectioN panels.
 4. An apparatus as in claim1 including a heat exchange medium storage reservoir disposed withinsaid heat exchange medium circulating path; said heat exchange reservoiradapted to conserve the thermal energy of said heat exchange medium. 5.An apparatus as in claim 1 including fan means disposed upwardly of saidevaporated coolant system and adapted to create a flow of air upwardlyaround said each of said heat rejection panels.
 6. An apparatus as inclaim 1 including an electrically solenoid operated dump valve disposedwithin said coolant reservoir and adopted to automatically flush saidreservoir at preselected intervals.